Polyethylene composition containing an nu-substituted oleamide



Unit? 1 Pat nt- .1 2,991,265.1 POLYETHYLENE COMPOSITION I CONTAINING ANN-SUBSTITUTED OLEAMIDE Clayton F. Clark, Overland-Park, andTRobert W.Hill,

. Leawood, Kans.-, assignors to Spencer Chemical Com- ;pany li ansasCityyMo a corporation of Missouri NoDrawing. Filed June 1'8, 1958, Ser.No, 742,755

,1. "5 Claims..,(Cl.260-;- .-,32.6), v

. invention relates to plastic compositions and, more t novelpolyethylenes of enhanced slip charsp'e'q fi' T1 a9 ri -t .7 vPolyethylene is one'of the most popular and well known thermoplasticsofthis plasticage. The number of varied uses inci'eases spectacularly'eachyear;""many"of these include the utilization of polyethylenefilm's; Polyethylene film is being used to package a wide and yariedlist of commercial commodities such as foods, meats, chemicals,pharmaceuticals, seeds, clothing, hardware, toys, etc. One of the moreimportant properties associated with polyethylene film is its'sliporfilm-to-film coefficient of friction. Slipf as it is known to thetrade, relates to the resistance of the film to a sliding action overanother film surface or over a metal surface, as manifested by thethinsheets of blown film sticking to one another. Poor slip characteristicsof polyethylene film are especially troublesome to .users of automaticpackaging equipment. Poor slip is a greater problem with blown film,which is usually thinner than extruded sheets, although there are alsomany applications of sheets in which an improved slip is alsoadvantageous.

The object of this invention is to provide plastic compositions havingan improvedslip or low'film-tofilm eoeflicient of friction. A furtherobject of this invention is to provide polyethylene compositions which,upon conversion to sheets or films, have an improved slip.

A still further object of this invention is to provide polyethylenefilms orsheets possessing improved slip characteristics.

There is provided by this invention novel plastic compositionscomprising polyethylene containing .a small amount of an additive whichenhances the slip of the polyethylene. Additives which have been foundto enhance or improve the slip of polyethylene when incorporated thereinmay be; conveniently divided into the following four groups:

1 GROUP 1 I N-substitutedderivatives of .oleamide in which the N-substituent is a long chain saturated or unsaturated aliphatic group,such? as higher alkyl or alkenylgroups. Some particularcompoundsiwithinithis group that might be named, andwhich are goodpolyethylene slip additives, are N-(noctyDoleamide,N-(n-dodecyDoleamide, N-(n-myristyDoleamide, N-(n-palmityDoleamid,N-(noctadecyl)oleamide 'an'd' 'N-'(n-oleyl)oleamide.

.eR vr 2 N-substituted derivatives of oleamide in which the N-substituent is a straight orl branched alkyl group, and particularlylower alk'ylgroups,"substituted'with one or more functional groups suchas the hydroxy group, carboxy group onthe.sulfowgroupwfl'ypical specificcompounds of this group which are highly :useful-for the describedpurpose are N-oleoyl glycine, N-oleoyl taurine,

N-.(2-hydroxyethyl) olean ideandN-(hydroxyi-butyholeamide.

GROUP3V N-oleyl derivatives amides which the---- alkyl moiety of thefatty acid may be a higher al kyl a The following example illustratesthe improved eflect Patented July 4, 1961 "ice N-mono-oleyl andN,N-dio1eyl derivatives of dibasi'c acid diamides, and particularly thecompounds N,N' -dioleyladipamide and N-monboleyladipamide.

Additives of the described types are solids 'at room temperature,insoluble in Water and soluble in most hot hydrocarbons. These compoundsare readily prepared by conventional processes such as by heatingtheappropriate fatty acid with'theappropriate amine at about 230 C. forabout 0.5 to 1 hour under an atmosphere of nitrogen. The product isrecovered from the reaction'mixture by the usual procedures.

The incorporation of a small amount of one or more of the describedadditives in polyethylene greatly reduces the polyethylene coefficientof friction. Polyethylene films and sheets and other products made frompolyethylene containing a small amount of an additive possess improvedslip characteristics.

Incorporation of the additive in the polyethylene may be effected byseveral different methods. For example, the additive may be added as asolid, in solution or in the form of a slurry to polyethylene in eitherthe mold ing powder or pellet for-m followed by tumbling and drying. Theadditive may also be incorporated by melt blending the ingredients in aconventional "apparatus, such as binary mixer, heated rolls or aplasticater.

Additives of the described types are effective slip agents whenincorporated in polyethylene to give a polyethylene compositioncontaining about 0.01% to about 1% by weight of the additive. Thepreferred-composition is about 0.05% to about 0.2% by weight of additivein polyethylene. Although more than 1% of additive maybe 1 incorporatedin polyethylene, larger amounts wouldnot generally be warranted.

It is to be understood that minor amounts of other desirable materials,such as high melting waxes, antioxidants, dyes and pigments, lubricants,antistatic agents, and the like, may also be present in amounts which donot affect the high slip properties of these polyethylene compositions.

The described additives are effective in improving the slipcharacteristics of all types of polyethylene, whether they be the morelinear polyethylenes prepared by the low pressure process, theconventional high pressure process polyethylenes of a lower density orthe medium density polyethylenes.

Although polyethylene containing one or more of the described additivesis particularly useful for improving the slip of products fabricated byextrusion into thin films sheets, blown tubing, and the like, it mayalso be cast or molded into films, sheets, rods, tubes and piping,filaments, and other shaped articles, having better slip than'similarproducts made of polyethylene containing no additive. In this regard,molded articles such as cups which tend to stick together when nestedaremore readily separated when the polyethylene contains at least one ofthe described additives. The polyethylene compositions of this inventionmay also be used for coating paper, cloth, wire, metal foil, glass fibermats, synthetic and natural textiles, etc., where good slip is desired.

Polyethylene to which at least one of the additives is added hasimproved blocking properties, that is, film made from such polyethylenehas much less tendency to block than an identical polyethylenecontaining no additive? of the additives on the slip of polyethylenesheet.

3 Example 1 Various additives of the described groups were introducedsingly into a commercial high pressure process type polyethylene havinga density of 0.92 and melt index of 2 by introducing the additives intoa commercial type Banhury and Banburying for 10 minutes at 190 F. Thepolyethylene was then sheeted on a roll mill, ground on a Wiley mill andscreened through a screen having 4 mm. openings and extruded into flatfilm on a 1-inch extruder equipped with a 6-inch flat film die. The filmwas aged by suspending in air at room temperature for at least 24 hours.The film was evaluated for slip by means of an inclined plane method,which consisted of stretching the film on an adjustable plane. A metalsled weighing 95 grams was placed on the film and one end of the planethen raised until the sled began to slide. The slope of the plane atthis point, expressed in degrees, was reported as the slip of theadditive. The following results were obtained:

The results clearly show the improved sl1'p" characteristics of thepolyethylene-additive compositions. The control containing no additiverequired an angle much higher than the polyethylene-additivecompositions in order to cause the sled to slide. We have found thatpolyethylene compositions which have a low film-to-metal coefiicient offriction will also have a comparably low film-to-film coeflicient offriction.

Various changes and modifications of the invention can be made and, tothe extent that such variations incorporate the spirit of thisinvention, they are intended to be included within the scope of theappended claims.

What is claimed is: t

1. A plastic composition comprising polyethylene and 0.01% to 1.0% byweight of an N-substituted oleamide selected from the group consistingof N-(hydroxy-substituted lower aIkyDQIeamide, N (carboxy substitutedlower alkyl)oleam.ide and N-(sulfo-substituted lower alkyl)oleamide.

TABLE Slip angle at cone, degrees 01- Addltlve Formula GROUP 1 llN-(n-octyl) oleamide CflHasCNH-(CHz)7CHn 23 ll N-(n-dodecyl) oleamideC11Hs5C--NH(CH,) CH 27 21 15 12 II N-(n-mynstyl) oleamide C1H;3CNH(CHz)1aCHa 28 it N-(n-palmityl) oleamide C17H33CNH(GH2)15CH1 24ll N-(n-octadecyl) olearmde CnHnC-NH-(CHDnCH: 18

N N-(n-oleyDoleaHllde CnHuCNH-(CH1)aCH=CH(CHz)1CH| 25 GROUP 2 N-oleoylglycine CuHaaC-NH-CHzCOOH 2t 21 22 ll Noleoyl taurlneCflHiaC-NH-CHICHQSOaH 28 i N-(Z-hydroxyethyl) oleamide.--.CnHuC-NH-CH:CH2OH 23 17 15 u I N-(hydroxy-t-butyl) oleamlde..C11H;;C-NH-(lJ-CH,OH 27 CH: GROUP 3 ll N-oleyl capramideCHa(CHa)sC'-NH-C1aHa5 30 ll N-OlBYl myrlstamlde CHs(CHq)nC-NHC;:HH 19 llN-oleyl palmitamlde CHs(CHz)uC-NH-C15Has 23 II N-oleyl steal-amideCHz(CHn)mC-NHC1BHas 27 N N-oleyl erucamlde CHa(CHn)1CH=CH(CHz)1iCNHC 5H|12 unonr 4 H (I? N ,N-dioleyl adipamide CiaHn--NHC-(CH:)4--C-NHC|eHu 28I H H N-monooleyl adipamxde HN-C-(CH1)4GNH-CiaHat 23 N own-Control (noadditive), 36.

2. A plastic composition comprising polyethylene and from 0.01% to 1.0%by weight of N-(hydroxy-t-butyl)- from 0.01% to 1.0% by weight ofN-oleoyl glycine. oleamide.

3. A plastic composition comprising polyethylene and from 0.01% to 1.0%by weight of N-oleoyl taurine. References Cited in the file of thispatent 4. A plastic composition comprising polyethylene and 5 from 0.01%to 1.0% by weight of N-(Z-hydroxyethyD- FOREIGN PATENTS oleamide.1,132,791 France Mar. 15, 1957 5. A plastic composition comprisingpolyethylene and UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTIONPatent No. 2,991,265 July 4",. 1961 Clayton F. Clark et a1,

It is hereby certified "that error appears in the above numbered pat entrequiring correction and that the said-Letters Patent. should read as"corrected below. r

Column 3, line 6, for "Ba'nbury and Banburying" read banbury andbanburying columns 3 and 4 in the table under the heading "0.5%" andopposite '"N-=(n-=dodecyl) oleamide" insert 7 1 Signed and sealed this21st day of November 1961.

(SEAL) Attest: V

ERNEST w. SWIDER DAVID L. LADD Attesting Officer Commissioner of Patentsus'coMM-Do

1. A PLASTIC COMPOSITION COMPRISING POLYETHYLENE AND 0.01% TO 1.0% BY WEIGHT OF AN N-SUBSTITUTED OLEAMIDE SELECTED FROM THE GROUP CONSISTING OF N-(HYDROXY-SUBSTITUTED LOWER ALKYL) OLEAMIDE, N - (CARBOXY - SUBSTITUTED LOWER ALKYL) OLEAMIDE AND N-(SULFO-SUBSTITUTED LOWER ALKYL) OLEAMIDE. 